Background

The genus Microthecium contains 31 species worldwide distributed. Most of them are saprobic on soil and plant debris, but a few have been reported as mycoparasites on hypocrealean fungi. By contrast, this genus has never been reported as phytopathogenic, nor endophytic.

Aims

To isolate and identify endophytic fungi from Mediterranean herbaceous plants and trees in order to contribute to the knowledge of the hosts and their geographical location. The present work has been focused on the study of endophytic fungi of hawthorn (Crataegus monogyna).

Methods

The following steps were taken: i, isolation of the fungal strain from living stems of C. monogyna; ii, cultural and micro-morphological study, and iii, sequence comparison of different genetic markers by BLAST search with sequences deposited in GenBank.

Results

At the present work we describe a new species of the genus, Microthecium pleomorphosporum, isolated from living stems of C. monogyna in Mallorca (Balearic Islands, Spain). This fungus is characterized by the production of non-ostiolate perithecia and two sorts of ascospores (some smooth-walled, others delicately reticulated) bearing a germ pore at each end which are frequently ornamented by a surrounding donut-like structures, and a phialidic asexual morph and bulbils. The morphologically closest related species is Microthecium tenuissimum, which has bigger ascospores and lacks asexual reproduction. Phylogenetically, M pleomorphosporum is close-related to other species of the genus, although no genetic marker that discriminates this new species from other phylogenetically closer ones could be elucidated as a gold standard.

Conclusions

M. pleomorphosporum, order Melanosporales, is reported here as the first endophytic species of C. monogyna.

中文翻译：

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来自马略卡岛（西班牙巴利阿里群岛）的小囊壳菌（Melanosporales、Sordariomycetes、Pezizomycotina、Ascomycota）的新内生物种

背景

Microthecium属包含 31 种，分布于世界各地。其中大多数是土壤和植物残体上的腐生菌，但据报道，少数是次生真菌上的真菌寄生虫。相比之下，该属从未被报道为植物病原性或内生性。

目标

从地中海草本植物和树木中分离和鉴定内生真菌，以有助于了解宿主及其地理位置。目前的工作重点是山楂内生真菌( Crataegus monogyna )的研究。

方法

采取以下步骤： i，从C. monogyna的活茎中分离真菌菌株；ii，培养和微形态学研究，以及 iii，通过 BLAST 搜索与 GenBank 中存储的序列进行不同遗传标记的序列比较。

结果

在目前的工作中，我们描述了该属的一个新种，Microthecium pleomorphosporum ，是从马略卡岛（西班牙巴利阿里群岛）的C. monogyna活茎中分离出来的。这种真菌的特征是产生无孔子囊壳和两种子囊孢子（一些是光滑壁的，另一些是精致的网状的），每端都有一个胚芽孔，这些孢子经常被周围的甜甜圈状结构所装饰，并且有一个花瓶无性生殖。变形和珠芽。形态上最接近的相关物种是Microthecium tenuissimum，它具有较大的子囊孢子并且缺乏无性繁殖。在系统发育上，多形孢分枝杆菌与该属的其他物种密切相关，尽管没有任何遗传标记可以将这个新物种与其他系统发育上更接近的物种区分开来，作为黄金标准。

结论

M. pleomorphosporum ，黑孢菌目，在此被报道为C. monogyna的第一个内生物种。